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ScienceShot: A New Type of 'Quasicrystal'

In 1982, Daniel Shechtman, an Israeli materials scientist, was first to spot a new type of irregular crystal, known as a quasicrystal. Unlike conventional crystals that have a regular repeating pattern to their member atoms, in quasicrystals the pattern is ordered but doesn’t repeat. Since Shechtman’s discovery, hundreds of quasicrystals have been discovered, most of which are alloys of two or three metals. Now, researchers in the United States report online today in Nature that they’ve added a new group to the list. The researchers added a layer of iron containing small molecules called ferrocenecarboxylic acid atop a gold surface. Rather than pairing up in “dimers” the way they normally do, interactions between the surface and neighboring molecules forced them to bind in rings that look like molecular rosettes, and in larger patterns including pentagons, stars, and rhombi (see above). The researchers suspect that this could open the door to the discovery of many other small molecule-based quasicrystals, though it’s unclear whether they will find practical uses.